drivers/rtc/rtc-cmos.c

   1 /*
   2  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
   3  *
   4  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
   5  * Copyright (C) 2006 David Brownell (convert to new framework)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 /*
  14  * The original "cmos clock" chip was an MC146818 chip, now obsolete.
  15  * That defined the register interface now provided by all PCs, some
  16  * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
  17  * integrate an MC146818 clone in their southbridge, and boards use
  18  * that instead of discrete clones like the DS12887 or M48T86.  There
  19  * are also clones that connect using the LPC bus.
  20  *
  21  * That register API is also used directly by various other drivers
  22  * (notably for integrated NVRAM), infrastructure (x86 has code to
  23  * bypass the RTC framework, directly reading the RTC during boot
  24  * and updating minutes/seconds for systems using NTP synch) and
  25  * utilities (like userspace 'hwclock', if no /dev node exists).
  26  *
  27  * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
  28  * interrupts disabled, holding the global rtc_lock, to exclude those
  29  * other drivers and utilities on correctly configured systems.
  30  */
  31
  32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34 #include <linux/kernel.h>
  35 #include <linux/module.h>
  36 #include <linux/init.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/platform_device.h>
  40 #include <linux/log2.h>
  41 #include <linux/pm.h>
  42 #include <linux/of.h>
  43 #include <linux/of_platform.h>
  44 #ifdef CONFIG_X86
  45 #include <asm/i8259.h>
  46 #endif
  47
  48 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  49 #include <linux/mc146818rtc.h>
  50
  51 /*
  52  * Use ACPI SCI to replace HPET interrupt for RTC Alarm event
  53  *
  54  * If cleared, ACPI SCI is only used to wake up the system from suspend
  55  *
  56  * If set, ACPI SCI is used to handle UIE/AIE and system wakeup
  57  */
  58
  59 static bool use_acpi_alarm;
  60 module_param(use_acpi_alarm, bool, 0444);
  61
  62 struct cmos_rtc {
  63         struct rtc_device       *rtc;
  64         struct device           *dev;
  65         int                     irq;
  66         struct resource         *iomem;
  67         time64_t                alarm_expires;
  68
  69         void                    (*wake_on)(struct device *);
  70         void                    (*wake_off)(struct device *);
  71
  72         u8                      enabled_wake;
  73         u8                      suspend_ctrl;
  74
  75         /* newer hardware extends the original register set */
  76         u8                      day_alrm;
  77         u8                      mon_alrm;
  78         u8                      century;
  79
  80         struct rtc_wkalrm       saved_wkalrm;
  81 };
  82
  83 /* both platform and pnp busses use negative numbers for invalid irqs */
  84 #define is_valid_irq(n)         ((n) > 0)
  85
  86 static const char driver_name[] = "rtc_cmos";
  87
  88 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
  89  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
  90  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
  91  */
  92 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
  93
  94 static inline int is_intr(u8 rtc_intr)
  95 {
  96         if (!(rtc_intr & RTC_IRQF))
  97                 return 0;
  98         return rtc_intr & RTC_IRQMASK;
  99 }
 100
 101 /*----------------------------------------------------------------*/
 102
 103 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
 104  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
 105  * used in a broken "legacy replacement" mode.  The breakage includes
 106  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
 107  * other (better) use.
 108  *
 109  * When that broken mode is in use, platform glue provides a partial
 110  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
 111  * want to use HPET for anything except those IRQs though...
 112  */
 113 #ifdef CONFIG_HPET_EMULATE_RTC
 114 #include <asm/hpet.h>
 115 #else
 116
 117 static inline int is_hpet_enabled(void)
 118 {
 119         return 0;
 120 }
 121
 122 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 123 {
 124         return 0;
 125 }
 126
 127 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 128 {
 129         return 0;
 130 }
 131
 132 static inline int
 133 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 134 {
 135         return 0;
 136 }
 137
 138 static inline int hpet_set_periodic_freq(unsigned long freq)
 139 {
 140         return 0;
 141 }
 142
 143 static inline int hpet_rtc_dropped_irq(void)
 144 {
 145         return 0;
 146 }
 147
 148 static inline int hpet_rtc_timer_init(void)
 149 {
 150         return 0;
 151 }
 152
 153 extern irq_handler_t hpet_rtc_interrupt;
 154
 155 static inline int hpet_register_irq_handler(irq_handler_t handler)
 156 {
 157         return 0;
 158 }
 159
 160 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 161 {
 162         return 0;
 163 }
 164
 165 #endif
 166
 167 /* Don't use HPET for RTC Alarm event if ACPI Fixed event is used */
 168 static int use_hpet_alarm(void)
 169 {
 170         return is_hpet_enabled() && !use_acpi_alarm;
 171 }
 172
 173 /*----------------------------------------------------------------*/
 174
 175 #ifdef RTC_PORT
 176
 177 /* Most newer x86 systems have two register banks, the first used
 178  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 179  * own rtc_lock ... and we won't worry about access during NMI.
 180  */
 181 #define can_bank2       true
 182
 183 static inline unsigned char cmos_read_bank2(unsigned char addr)
 184 {
 185         outb(addr, RTC_PORT(2));
 186         return inb(RTC_PORT(3));
 187 }
 188
 189 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 190 {
 191         outb(addr, RTC_PORT(2));
 192         outb(val, RTC_PORT(3));
 193 }
 194
 195 #else
 196
 197 #define can_bank2       false
 198
 199 static inline unsigned char cmos_read_bank2(unsigned char addr)
 200 {
 201         return 0;
 202 }
 203
 204 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 205 {
 206 }
 207
 208 #endif
 209
 210 /*----------------------------------------------------------------*/
 211
 212 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 213 {
 214         /*
 215          * If pm_trace abused the RTC for storage, set the timespec to 0,
 216          * which tells the caller that this RTC value is unusable.
 217          */
 218         if (!pm_trace_rtc_valid())
 219                 return -EIO;
 220
 221         /* REVISIT:  if the clock has a "century" register, use
 222          * that instead of the heuristic in mc146818_get_time().
 223          * That'll make Y3K compatility (year > 2070) easy!
 224          */
 225         mc146818_get_time(t);
 226         return 0;
 227 }
 228
 229 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 230 {
 231         /* REVISIT:  set the "century" register if available
 232          *
 233          * NOTE: this ignores the issue whereby updating the seconds
 234          * takes effect exactly 500ms after we write the register.
 235          * (Also queueing and other delays before we get this far.)
 236          */
 237         return mc146818_set_time(t);
 238 }
 239
 240 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 241 {
 242         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 243         unsigned char   rtc_control;
 244
 245         if (!is_valid_irq(cmos->irq))
 246                 return -EIO;
 247
 248         /* Basic alarms only support hour, minute, and seconds fields.
 249          * Some also support day and month, for alarms up to a year in
 250          * the future.
 251          */
 252
 253         spin_lock_irq(&rtc_lock);
 254         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 255         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 256         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 257
 258         if (cmos->day_alrm) {
 259                 /* ignore upper bits on readback per ACPI spec */
 260                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 261                 if (!t->time.tm_mday)
 262                         t->time.tm_mday = -1;
 263
 264                 if (cmos->mon_alrm) {
 265                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 266                         if (!t->time.tm_mon)
 267                                 t->time.tm_mon = -1;
 268                 }
 269         }
 270
 271         rtc_control = CMOS_READ(RTC_CONTROL);
 272         spin_unlock_irq(&rtc_lock);
 273
 274         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 275                 if (((unsigned)t->time.tm_sec) < 0x60)
 276                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 277                 else
 278                         t->time.tm_sec = -1;
 279                 if (((unsigned)t->time.tm_min) < 0x60)
 280                         t->time.tm_min = bcd2bin(t->time.tm_min);
 281                 else
 282                         t->time.tm_min = -1;
 283                 if (((unsigned)t->time.tm_hour) < 0x24)
 284                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 285                 else
 286                         t->time.tm_hour = -1;
 287
 288                 if (cmos->day_alrm) {
 289                         if (((unsigned)t->time.tm_mday) <= 0x31)
 290                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 291                         else
 292                                 t->time.tm_mday = -1;
 293
 294                         if (cmos->mon_alrm) {
 295                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 296                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 297                                 else
 298                                         t->time.tm_mon = -1;
 299                         }
 300                 }
 301         }
 302
 303         t->enabled = !!(rtc_control & RTC_AIE);
 304         t->pending = 0;
 305
 306         return 0;
 307 }
 308
 309 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 310 {
 311         unsigned char   rtc_intr;
 312
 313         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 314          * allegedly some older rtcs need that to handle irqs properly
 315          */
 316         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 317
 318         if (use_hpet_alarm())
 319                 return;
 320
 321         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 322         if (is_intr(rtc_intr))
 323                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 324 }
 325
 326 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 327 {
 328         unsigned char   rtc_control;
 329
 330         /* flush any pending IRQ status, notably for update irqs,
 331          * before we enable new IRQs
 332          */
 333         rtc_control = CMOS_READ(RTC_CONTROL);
 334         cmos_checkintr(cmos, rtc_control);
 335
 336         rtc_control |= mask;
 337         CMOS_WRITE(rtc_control, RTC_CONTROL);
 338         if (use_hpet_alarm())
 339                 hpet_set_rtc_irq_bit(mask);
 340
 341         if ((mask & RTC_AIE) && use_acpi_alarm) {
 342                 if (cmos->wake_on)
 343                         cmos->wake_on(cmos->dev);
 344         }
 345
 346         cmos_checkintr(cmos, rtc_control);
 347 }
 348
 349 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 350 {
 351         unsigned char   rtc_control;
 352
 353         rtc_control = CMOS_READ(RTC_CONTROL);
 354         rtc_control &= ~mask;
 355         CMOS_WRITE(rtc_control, RTC_CONTROL);
 356         if (use_hpet_alarm())
 357                 hpet_mask_rtc_irq_bit(mask);
 358
 359         if ((mask & RTC_AIE) && use_acpi_alarm) {
 360                 if (cmos->wake_off)
 361                         cmos->wake_off(cmos->dev);
 362         }
 363
 364         cmos_checkintr(cmos, rtc_control);
 365 }
 366
 367 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 368 {
 369         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 370         struct rtc_time now;
 371
 372         cmos_read_time(dev, &now);
 373
 374         if (!cmos->day_alrm) {
 375                 time64_t t_max_date;
 376                 time64_t t_alrm;
 377
 378                 t_max_date = rtc_tm_to_time64(&now);
 379                 t_max_date += 24 * 60 * 60 - 1;
 380                 t_alrm = rtc_tm_to_time64(&t->time);
 381                 if (t_alrm > t_max_date) {
 382                         dev_err(dev,
 383                                 "Alarms can be up to one day in the future\n");
 384                         return -EINVAL;
 385                 }
 386         } else if (!cmos->mon_alrm) {
 387                 struct rtc_time max_date = now;
 388                 time64_t t_max_date;
 389                 time64_t t_alrm;
 390                 int max_mday;
 391
 392                 if (max_date.tm_mon == 11) {
 393                         max_date.tm_mon = 0;
 394                         max_date.tm_year += 1;
 395                 } else {
 396                         max_date.tm_mon += 1;
 397                 }
 398                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 399                 if (max_date.tm_mday > max_mday)
 400                         max_date.tm_mday = max_mday;
 401
 402                 t_max_date = rtc_tm_to_time64(&max_date);
 403                 t_max_date -= 1;
 404                 t_alrm = rtc_tm_to_time64(&t->time);
 405                 if (t_alrm > t_max_date) {
 406                         dev_err(dev,
 407                                 "Alarms can be up to one month in the future\n");
 408                         return -EINVAL;
 409                 }
 410         } else {
 411                 struct rtc_time max_date = now;
 412                 time64_t t_max_date;
 413                 time64_t t_alrm;
 414                 int max_mday;
 415
 416                 max_date.tm_year += 1;
 417                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 418                 if (max_date.tm_mday > max_mday)
 419                         max_date.tm_mday = max_mday;
 420
 421                 t_max_date = rtc_tm_to_time64(&max_date);
 422                 t_max_date -= 1;
 423                 t_alrm = rtc_tm_to_time64(&t->time);
 424                 if (t_alrm > t_max_date) {
 425                         dev_err(dev,
 426                                 "Alarms can be up to one year in the future\n");
 427                         return -EINVAL;
 428                 }
 429         }
 430
 431         return 0;
 432 }
 433
 434 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 435 {
 436         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 437         unsigned char mon, mday, hrs, min, sec, rtc_control;
 438         int ret;
 439
 440         if (!is_valid_irq(cmos->irq))
 441                 return -EIO;
 442
 443         ret = cmos_validate_alarm(dev, t);
 444         if (ret < 0)
 445                 return ret;
 446
 447         mon = t->time.tm_mon + 1;
 448         mday = t->time.tm_mday;
 449         hrs = t->time.tm_hour;
 450         min = t->time.tm_min;
 451         sec = t->time.tm_sec;
 452
 453         rtc_control = CMOS_READ(RTC_CONTROL);
 454         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 455                 /* Writing 0xff means "don't care" or "match all".  */
 456                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 457                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 458                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 459                 min = (min < 60) ? bin2bcd(min) : 0xff;
 460                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 461         }
 462
 463         spin_lock_irq(&rtc_lock);
 464
 465         /* next rtc irq must not be from previous alarm setting */
 466         cmos_irq_disable(cmos, RTC_AIE);
 467
 468         /* update alarm */
 469         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 470         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 471         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 472
 473         /* the system may support an "enhanced" alarm */
 474         if (cmos->day_alrm) {
 475                 CMOS_WRITE(mday, cmos->day_alrm);
 476                 if (cmos->mon_alrm)
 477                         CMOS_WRITE(mon, cmos->mon_alrm);
 478         }
 479
 480         if (use_hpet_alarm()) {
 481                 /*
 482                  * FIXME the HPET alarm glue currently ignores day_alrm
 483                  * and mon_alrm ...
 484                  */
 485                 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min,
 486                                     t->time.tm_sec);
 487         }
 488
 489         if (t->enabled)
 490                 cmos_irq_enable(cmos, RTC_AIE);
 491
 492         spin_unlock_irq(&rtc_lock);
 493
 494         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 495
 496         return 0;
 497 }
 498
 499 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 500 {
 501         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 502         unsigned long   flags;
 503
 504         if (!is_valid_irq(cmos->irq))
 505                 return -EINVAL;
 506
 507         spin_lock_irqsave(&rtc_lock, flags);
 508
 509         if (enabled)
 510                 cmos_irq_enable(cmos, RTC_AIE);
 511         else
 512                 cmos_irq_disable(cmos, RTC_AIE);
 513
 514         spin_unlock_irqrestore(&rtc_lock, flags);
 515         return 0;
 516 }
 517
 518 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 519
 520 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 521 {
 522         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 523         unsigned char   rtc_control, valid;
 524
 525         spin_lock_irq(&rtc_lock);
 526         rtc_control = CMOS_READ(RTC_CONTROL);
 527         valid = CMOS_READ(RTC_VALID);
 528         spin_unlock_irq(&rtc_lock);
 529
 530         /* NOTE:  at least ICH6 reports battery status using a different
 531          * (non-RTC) bit; and SQWE is ignored on many current systems.
 532          */
 533         seq_printf(seq,
 534                    "periodic_IRQ\t: %s\n"
 535                    "update_IRQ\t: %s\n"
 536                    "HPET_emulated\t: %s\n"
 537                    // "square_wave\t: %s\n"
 538                    "BCD\t\t: %s\n"
 539                    "DST_enable\t: %s\n"
 540                    "periodic_freq\t: %d\n"
 541                    "batt_status\t: %s\n",
 542                    (rtc_control & RTC_PIE) ? "yes" : "no",
 543                    (rtc_control & RTC_UIE) ? "yes" : "no",
 544                    use_hpet_alarm() ? "yes" : "no",
 545                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 546                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 547                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 548                    cmos->rtc->irq_freq,
 549                    (valid & RTC_VRT) ? "okay" : "dead");
 550
 551         return 0;
 552 }
 553
 554 #else
 555 #define cmos_procfs     NULL
 556 #endif
 557
 558 static const struct rtc_class_ops cmos_rtc_ops = {
 559         .read_time              = cmos_read_time,
 560         .set_time               = cmos_set_time,
 561         .read_alarm             = cmos_read_alarm,
 562         .set_alarm              = cmos_set_alarm,
 563         .proc                   = cmos_procfs,
 564         .alarm_irq_enable       = cmos_alarm_irq_enable,
 565 };
 566
 567 /*----------------------------------------------------------------*/
 568
 569 /*
 570  * All these chips have at least 64 bytes of address space, shared by
 571  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 572  * by boot firmware.  Modern chips have 128 or 256 bytes.
 573  */
 574
 575 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 576
 577 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 578                            size_t count)
 579 {
 580         unsigned char *buf = val;
 581         int     retval;
 582
 583         off += NVRAM_OFFSET;
 584         spin_lock_irq(&rtc_lock);
 585         for (retval = 0; count; count--, off++, retval++) {
 586                 if (off < 128)
 587                         *buf++ = CMOS_READ(off);
 588                 else if (can_bank2)
 589                         *buf++ = cmos_read_bank2(off);
 590                 else
 591                         break;
 592         }
 593         spin_unlock_irq(&rtc_lock);
 594
 595         return retval;
 596 }
 597
 598 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 599                             size_t count)
 600 {
 601         struct cmos_rtc *cmos = priv;
 602         unsigned char   *buf = val;
 603         int             retval;
 604
 605         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 606          * checksum on part of the NVRAM data.  That's currently ignored
 607          * here.  If userspace is smart enough to know what fields of
 608          * NVRAM to update, updating checksums is also part of its job.
 609          */
 610         off += NVRAM_OFFSET;
 611         spin_lock_irq(&rtc_lock);
 612         for (retval = 0; count; count--, off++, retval++) {
 613                 /* don't trash RTC registers */
 614                 if (off == cmos->day_alrm
 615                                 || off == cmos->mon_alrm
 616                                 || off == cmos->century)
 617                         buf++;
 618                 else if (off < 128)
 619                         CMOS_WRITE(*buf++, off);
 620                 else if (can_bank2)
 621                         cmos_write_bank2(*buf++, off);
 622                 else
 623                         break;
 624         }
 625         spin_unlock_irq(&rtc_lock);
 626
 627         return retval;
 628 }
 629
 630 /*----------------------------------------------------------------*/
 631
 632 static struct cmos_rtc  cmos_rtc;
 633
 634 static irqreturn_t cmos_interrupt(int irq, void *p)
 635 {
 636         u8              irqstat;
 637         u8              rtc_control;
 638
 639         spin_lock(&rtc_lock);
 640
 641         /* When the HPET interrupt handler calls us, the interrupt
 642          * status is passed as arg1 instead of the irq number.  But
 643          * always clear irq status, even when HPET is in the way.
 644          *
 645          * Note that HPET and RTC are almost certainly out of phase,
 646          * giving different IRQ status ...
 647          */
 648         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 649         rtc_control = CMOS_READ(RTC_CONTROL);
 650         if (use_hpet_alarm())
 651                 irqstat = (unsigned long)irq & 0xF0;
 652
 653         /* If we were suspended, RTC_CONTROL may not be accurate since the
 654          * bios may have cleared it.
 655          */
 656         if (!cmos_rtc.suspend_ctrl)
 657                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 658         else
 659                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 660
 661         /* All Linux RTC alarms should be treated as if they were oneshot.
 662          * Similar code may be needed in system wakeup paths, in case the
 663          * alarm woke the system.
 664          */
 665         if (irqstat & RTC_AIE) {
 666                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 667                 rtc_control &= ~RTC_AIE;
 668                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 669                 if (use_hpet_alarm())
 670                         hpet_mask_rtc_irq_bit(RTC_AIE);
 671                 CMOS_READ(RTC_INTR_FLAGS);
 672         }
 673         spin_unlock(&rtc_lock);
 674
 675         if (is_intr(irqstat)) {
 676                 rtc_update_irq(p, 1, irqstat);
 677                 return IRQ_HANDLED;
 678         } else
 679                 return IRQ_NONE;
 680 }
 681
 682 #ifdef  CONFIG_PNP
 683 #define INITSECTION
 684
 685 #else
 686 #define INITSECTION     __init
 687 #endif
 688
 689 static int INITSECTION
 690 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 691 {
 692         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 693         int                             retval = 0;
 694         unsigned char                   rtc_control;
 695         unsigned                        address_space;
 696         u32                             flags = 0;
 697         struct nvmem_config nvmem_cfg = {
 698                 .name = "cmos_nvram",
 699                 .word_size = 1,
 700                 .stride = 1,
 701                 .reg_read = cmos_nvram_read,
 702                 .reg_write = cmos_nvram_write,
 703                 .priv = &cmos_rtc,
 704         };
 705
 706         /* there can be only one ... */
 707         if (cmos_rtc.dev)
 708                 return -EBUSY;
 709
 710         if (!ports)
 711                 return -ENODEV;
 712
 713         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 714          *
 715          * REVISIT non-x86 systems may instead use memory space resources
 716          * (needing ioremap etc), not i/o space resources like this ...
 717          */
 718         if (RTC_IOMAPPED)
 719                 ports = request_region(ports->start, resource_size(ports),
 720                                        driver_name);
 721         else
 722                 ports = request_mem_region(ports->start, resource_size(ports),
 723                                            driver_name);
 724         if (!ports) {
 725                 dev_dbg(dev, "i/o registers already in use\n");
 726                 return -EBUSY;
 727         }
 728
 729         cmos_rtc.irq = rtc_irq;
 730         cmos_rtc.iomem = ports;
 731
 732         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 733          * driver did, but don't reject unknown configs.   Old hardware
 734          * won't address 128 bytes.  Newer chips have multiple banks,
 735          * though they may not be listed in one I/O resource.
 736          */
 737 #if     defined(CONFIG_ATARI)
 738         address_space = 64;
 739 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 740                         || defined(__sparc__) || defined(__mips__) \
 741                         || defined(__powerpc__)
 742         address_space = 128;
 743 #else
 744 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 745         address_space = 128;
 746 #endif
 747         if (can_bank2 && ports->end > (ports->start + 1))
 748                 address_space = 256;
 749
 750         /* For ACPI systems extension info comes from the FADT.  On others,
 751          * board specific setup provides it as appropriate.  Systems where
 752          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 753          * some almost-clones) can provide hooks to make that behave.
 754          *
 755          * Note that ACPI doesn't preclude putting these registers into
 756          * "extended" areas of the chip, including some that we won't yet
 757          * expect CMOS_READ and friends to handle.
 758          */
 759         if (info) {
 760                 if (info->flags)
 761                         flags = info->flags;
 762                 if (info->address_space)
 763                         address_space = info->address_space;
 764
 765                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 766                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 767                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 768                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 769                 if (info->rtc_century && info->rtc_century < 128)
 770                         cmos_rtc.century = info->rtc_century;
 771
 772                 if (info->wake_on && info->wake_off) {
 773                         cmos_rtc.wake_on = info->wake_on;
 774                         cmos_rtc.wake_off = info->wake_off;
 775                 }
 776         }
 777
 778         cmos_rtc.dev = dev;
 779         dev_set_drvdata(dev, &cmos_rtc);
 780
 781         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 782         if (IS_ERR(cmos_rtc.rtc)) {
 783                 retval = PTR_ERR(cmos_rtc.rtc);
 784                 goto cleanup0;
 785         }
 786
 787         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 788
 789         spin_lock_irq(&rtc_lock);
 790
 791         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 792                 /* force periodic irq to CMOS reset default of 1024Hz;
 793                  *
 794                  * REVISIT it's been reported that at least one x86_64 ALI
 795                  * mobo doesn't use 32KHz here ... for portability we might
 796                  * need to do something about other clock frequencies.
 797                  */
 798                 cmos_rtc.rtc->irq_freq = 1024;
 799                 if (use_hpet_alarm())
 800                         hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 801                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 802         }
 803
 804         /* disable irqs */
 805         if (is_valid_irq(rtc_irq))
 806                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 807
 808         rtc_control = CMOS_READ(RTC_CONTROL);
 809
 810         spin_unlock_irq(&rtc_lock);
 811
 812         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 813                 dev_warn(dev, "only 24-hr supported\n");
 814                 retval = -ENXIO;
 815                 goto cleanup1;
 816         }
 817
 818         if (use_hpet_alarm())
 819                 hpet_rtc_timer_init();
 820
 821         if (is_valid_irq(rtc_irq)) {
 822                 irq_handler_t rtc_cmos_int_handler;
 823
 824                 if (use_hpet_alarm()) {
 825                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 826                         retval = hpet_register_irq_handler(cmos_interrupt);
 827                         if (retval) {
 828                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 829                                 dev_warn(dev, "hpet_register_irq_handler "
 830                                                 " failed in rtc_init().");
 831                                 goto cleanup1;
 832                         }
 833                 } else
 834                         rtc_cmos_int_handler = cmos_interrupt;
 835
 836                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 837                                 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
 838                                 cmos_rtc.rtc);
 839                 if (retval < 0) {
 840                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 841                         goto cleanup1;
 842                 }
 843         }
 844
 845         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 846         cmos_rtc.rtc->nvram_old_abi = true;
 847         retval = rtc_register_device(cmos_rtc.rtc);
 848         if (retval)
 849                 goto cleanup2;
 850
 851         /* export at least the first block of NVRAM */
 852         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 853         if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
 854                 dev_err(dev, "nvmem registration failed\n");
 855
 856         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 857                  !is_valid_irq(rtc_irq) ? "no alarms" :
 858                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 859                  cmos_rtc.day_alrm ? "alarms up to one month" :
 860                  "alarms up to one day",
 861                  cmos_rtc.century ? ", y3k" : "",
 862                  nvmem_cfg.size,
 863                  use_hpet_alarm() ? ", hpet irqs" : "");
 864
 865         return 0;
 866
 867 cleanup2:
 868         if (is_valid_irq(rtc_irq))
 869                 free_irq(rtc_irq, cmos_rtc.rtc);
 870 cleanup1:
 871         cmos_rtc.dev = NULL;
 872 cleanup0:
 873         if (RTC_IOMAPPED)
 874                 release_region(ports->start, resource_size(ports));
 875         else
 876                 release_mem_region(ports->start, resource_size(ports));
 877         return retval;
 878 }
 879
 880 static void cmos_do_shutdown(int rtc_irq)
 881 {
 882         spin_lock_irq(&rtc_lock);
 883         if (is_valid_irq(rtc_irq))
 884                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 885         spin_unlock_irq(&rtc_lock);
 886 }
 887
 888 static void cmos_do_remove(struct device *dev)
 889 {
 890         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 891         struct resource *ports;
 892
 893         cmos_do_shutdown(cmos->irq);
 894
 895         if (is_valid_irq(cmos->irq)) {
 896                 free_irq(cmos->irq, cmos->rtc);
 897                 if (use_hpet_alarm())
 898                         hpet_unregister_irq_handler(cmos_interrupt);
 899         }
 900
 901         cmos->rtc = NULL;
 902
 903         ports = cmos->iomem;
 904         if (RTC_IOMAPPED)
 905                 release_region(ports->start, resource_size(ports));
 906         else
 907                 release_mem_region(ports->start, resource_size(ports));
 908         cmos->iomem = NULL;
 909
 910         cmos->dev = NULL;
 911 }
 912
 913 static int cmos_aie_poweroff(struct device *dev)
 914 {
 915         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 916         struct rtc_time now;
 917         time64_t t_now;
 918         int retval = 0;
 919         unsigned char rtc_control;
 920
 921         if (!cmos->alarm_expires)
 922                 return -EINVAL;
 923
 924         spin_lock_irq(&rtc_lock);
 925         rtc_control = CMOS_READ(RTC_CONTROL);
 926         spin_unlock_irq(&rtc_lock);
 927
 928         /* We only care about the situation where AIE is disabled. */
 929         if (rtc_control & RTC_AIE)
 930                 return -EBUSY;
 931
 932         cmos_read_time(dev, &now);
 933         t_now = rtc_tm_to_time64(&now);
 934
 935         /*
 936          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 937          * automatically right after shutdown on some buggy boxes.
 938          * This automatic rebooting issue won't happen when the alarm
 939          * time is larger than now+1 seconds.
 940          *
 941          * If the alarm time is equal to now+1 seconds, the issue can be
 942          * prevented by cancelling the alarm.
 943          */
 944         if (cmos->alarm_expires == t_now + 1) {
 945                 struct rtc_wkalrm alarm;
 946
 947                 /* Cancel the AIE timer by configuring the past time. */
 948                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 949                 alarm.enabled = 0;
 950                 retval = cmos_set_alarm(dev, &alarm);
 951         } else if (cmos->alarm_expires > t_now + 1) {
 952                 retval = -EBUSY;
 953         }
 954
 955         return retval;
 956 }
 957
 958 static int cmos_suspend(struct device *dev)
 959 {
 960         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 961         unsigned char   tmp;
 962
 963         /* only the alarm might be a wakeup event source */
 964         spin_lock_irq(&rtc_lock);
 965         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 966         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 967                 unsigned char   mask;
 968
 969                 if (device_may_wakeup(dev))
 970                         mask = RTC_IRQMASK & ~RTC_AIE;
 971                 else
 972                         mask = RTC_IRQMASK;
 973                 tmp &= ~mask;
 974                 CMOS_WRITE(tmp, RTC_CONTROL);
 975                 if (use_hpet_alarm())
 976                         hpet_mask_rtc_irq_bit(mask);
 977                 cmos_checkintr(cmos, tmp);
 978         }
 979         spin_unlock_irq(&rtc_lock);
 980
 981         if ((tmp & RTC_AIE) && !use_acpi_alarm) {
 982                 cmos->enabled_wake = 1;
 983                 if (cmos->wake_on)
 984                         cmos->wake_on(dev);
 985                 else
 986                         enable_irq_wake(cmos->irq);
 987         }
 988
 989         cmos_read_alarm(dev, &cmos->saved_wkalrm);
 990
 991         dev_dbg(dev, "suspend%s, ctrl %02x\n",
 992                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 993                         tmp);
 994
 995         return 0;
 996 }
 997
 998 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
 999  * after a detour through G3 "mechanical off", although the ACPI spec
1000  * says wakeup should only work from G1/S4 "hibernate".  To most users,
1001  * distinctions between S4 and S5 are pointless.  So when the hardware
1002  * allows, don't draw that distinction.
1003  */
1004 static inline int cmos_poweroff(struct device *dev)
1005 {
1006         if (!IS_ENABLED(CONFIG_PM))
1007                 return -ENOSYS;
1008
1009         return cmos_suspend(dev);
1010 }
1011
1012 static void cmos_check_wkalrm(struct device *dev)
1013 {
1014         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1015         struct rtc_wkalrm current_alarm;
1016         time64_t t_now;
1017         time64_t t_current_expires;
1018         time64_t t_saved_expires;
1019         struct rtc_time now;
1020
1021         /* Check if we have RTC Alarm armed */
1022         if (!(cmos->suspend_ctrl & RTC_AIE))
1023                 return;
1024
1025         cmos_read_time(dev, &now);
1026         t_now = rtc_tm_to_time64(&now);
1027
1028         /*
1029          * ACPI RTC wake event is cleared after resume from STR,
1030          * ACK the rtc irq here
1031          */
1032         if (t_now >= cmos->alarm_expires && use_acpi_alarm) {
1033                 cmos_interrupt(0, (void *)cmos->rtc);
1034                 return;
1035         }
1036
1037         cmos_read_alarm(dev, &current_alarm);
1038         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
1039         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
1040         if (t_current_expires != t_saved_expires ||
1041             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
1042                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
1043         }
1044 }
1045
1046 static void cmos_check_acpi_rtc_status(struct device *dev,
1047                                        unsigned char *rtc_control);
1048
1049 static int __maybe_unused cmos_resume(struct device *dev)
1050 {
1051         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1052         unsigned char tmp;
1053
1054         if (cmos->enabled_wake && !use_acpi_alarm) {
1055                 if (cmos->wake_off)
1056                         cmos->wake_off(dev);
1057                 else
1058                         disable_irq_wake(cmos->irq);
1059                 cmos->enabled_wake = 0;
1060         }
1061
1062         /* The BIOS might have changed the alarm, restore it */
1063         cmos_check_wkalrm(dev);
1064
1065         spin_lock_irq(&rtc_lock);
1066         tmp = cmos->suspend_ctrl;
1067         cmos->suspend_ctrl = 0;
1068         /* re-enable any irqs previously active */
1069         if (tmp & RTC_IRQMASK) {
1070                 unsigned char   mask;
1071
1072                 if (device_may_wakeup(dev) && use_hpet_alarm())
1073                         hpet_rtc_timer_init();
1074
1075                 do {
1076                         CMOS_WRITE(tmp, RTC_CONTROL);
1077                         if (use_hpet_alarm())
1078                                 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1079
1080                         mask = CMOS_READ(RTC_INTR_FLAGS);
1081                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1082                         if (!use_hpet_alarm() || !is_intr(mask))
1083                                 break;
1084
1085                         /* force one-shot behavior if HPET blocked
1086                          * the wake alarm's irq
1087                          */
1088                         rtc_update_irq(cmos->rtc, 1, mask);
1089                         tmp &= ~RTC_AIE;
1090                         hpet_mask_rtc_irq_bit(RTC_AIE);
1091                 } while (mask & RTC_AIE);
1092
1093                 if (tmp & RTC_AIE)
1094                         cmos_check_acpi_rtc_status(dev, &tmp);
1095         }
1096         spin_unlock_irq(&rtc_lock);
1097
1098         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1099
1100         return 0;
1101 }
1102
1103 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1104
1105 /*----------------------------------------------------------------*/
1106
1107 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1108  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1109  * probably list them in similar PNPBIOS tables; so PNP is more common.
1110  *
1111  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1112  * predate even PNPBIOS should set up platform_bus devices.
1113  */
1114
1115 #ifdef  CONFIG_ACPI
1116
1117 #include <linux/acpi.h>
1118
1119 static u32 rtc_handler(void *context)
1120 {
1121         struct device *dev = context;
1122         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1123         unsigned char rtc_control = 0;
1124         unsigned char rtc_intr;
1125         unsigned long flags;
1126
1127
1128         /*
1129          * Always update rtc irq when ACPI is used as RTC Alarm.
1130          * Or else, ACPI SCI is enabled during suspend/resume only,
1131          * update rtc irq in that case.
1132          */
1133         if (use_acpi_alarm)
1134                 cmos_interrupt(0, (void *)cmos->rtc);
1135         else {
1136                 /* Fix me: can we use cmos_interrupt() here as well? */
1137                 spin_lock_irqsave(&rtc_lock, flags);
1138                 if (cmos_rtc.suspend_ctrl)
1139                         rtc_control = CMOS_READ(RTC_CONTROL);
1140                 if (rtc_control & RTC_AIE) {
1141                         cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1142                         CMOS_WRITE(rtc_control, RTC_CONTROL);
1143                         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1144                         rtc_update_irq(cmos->rtc, 1, rtc_intr);
1145                 }
1146                 spin_unlock_irqrestore(&rtc_lock, flags);
1147         }
1148
1149         pm_wakeup_hard_event(dev);
1150         acpi_clear_event(ACPI_EVENT_RTC);
1151         acpi_disable_event(ACPI_EVENT_RTC, 0);
1152         return ACPI_INTERRUPT_HANDLED;
1153 }
1154
1155 static inline void rtc_wake_setup(struct device *dev)
1156 {
1157         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1158         /*
1159          * After the RTC handler is installed, the Fixed_RTC event should
1160          * be disabled. Only when the RTC alarm is set will it be enabled.
1161          */
1162         acpi_clear_event(ACPI_EVENT_RTC);
1163         acpi_disable_event(ACPI_EVENT_RTC, 0);
1164 }
1165
1166 static void rtc_wake_on(struct device *dev)
1167 {
1168         acpi_clear_event(ACPI_EVENT_RTC);
1169         acpi_enable_event(ACPI_EVENT_RTC, 0);
1170 }
1171
1172 static void rtc_wake_off(struct device *dev)
1173 {
1174         acpi_disable_event(ACPI_EVENT_RTC, 0);
1175 }
1176
1177 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1178  * its device node and pass extra config data.  This helps its driver use
1179  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1180  * that this board's RTC is wakeup-capable (per ACPI spec).
1181  */
1182 static struct cmos_rtc_board_info acpi_rtc_info;
1183
1184 static void cmos_wake_setup(struct device *dev)
1185 {
1186         if (acpi_disabled)
1187                 return;
1188
1189         rtc_wake_setup(dev);
1190         acpi_rtc_info.wake_on = rtc_wake_on;
1191         acpi_rtc_info.wake_off = rtc_wake_off;
1192
1193         /* workaround bug in some ACPI tables */
1194         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1195                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1196                         acpi_gbl_FADT.month_alarm);
1197                 acpi_gbl_FADT.month_alarm = 0;
1198         }
1199
1200         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1201         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1202         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1203
1204         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1205         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1206                 dev_info(dev, "RTC can wake from S4\n");
1207
1208         dev->platform_data = &acpi_rtc_info;
1209
1210         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1211         device_init_wakeup(dev, 1);
1212 }
1213
1214 static void cmos_check_acpi_rtc_status(struct device *dev,
1215                                        unsigned char *rtc_control)
1216 {
1217         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1218         acpi_event_status rtc_status;
1219         acpi_status status;
1220
1221         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1222                 return;
1223
1224         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1225         if (ACPI_FAILURE(status)) {
1226                 dev_err(dev, "Could not get RTC status\n");
1227         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1228                 unsigned char mask;
1229                 *rtc_control &= ~RTC_AIE;
1230                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1231                 mask = CMOS_READ(RTC_INTR_FLAGS);
1232                 rtc_update_irq(cmos->rtc, 1, mask);
1233         }
1234 }
1235
1236 #else
1237
1238 static void cmos_wake_setup(struct device *dev)
1239 {
1240 }
1241
1242 static void cmos_check_acpi_rtc_status(struct device *dev,
1243                                        unsigned char *rtc_control)
1244 {
1245 }
1246
1247 #endif
1248
1249 #ifdef  CONFIG_PNP
1250
1251 #include <linux/pnp.h>
1252
1253 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1254 {
1255         cmos_wake_setup(&pnp->dev);
1256
1257         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1258                 unsigned int irq = 0;
1259 #ifdef CONFIG_X86
1260                 /* Some machines contain a PNP entry for the RTC, but
1261                  * don't define the IRQ. It should always be safe to
1262                  * hardcode it on systems with a legacy PIC.
1263                  */
1264                 if (nr_legacy_irqs())
1265                         irq = 8;
1266 #endif
1267                 return cmos_do_probe(&pnp->dev,
1268                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1269         } else {
1270                 return cmos_do_probe(&pnp->dev,
1271                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1272                                 pnp_irq(pnp, 0));
1273         }
1274 }
1275
1276 static void cmos_pnp_remove(struct pnp_dev *pnp)
1277 {
1278         cmos_do_remove(&pnp->dev);
1279 }
1280
1281 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1282 {
1283         struct device *dev = &pnp->dev;
1284         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1285
1286         if (system_state == SYSTEM_POWER_OFF) {
1287                 int retval = cmos_poweroff(dev);
1288
1289                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1290                         return;
1291         }
1292
1293         cmos_do_shutdown(cmos->irq);
1294 }
1295
1296 static const struct pnp_device_id rtc_ids[] = {
1297         { .id = "PNP0b00", },
1298         { .id = "PNP0b01", },
1299         { .id = "PNP0b02", },
1300         { },
1301 };
1302 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1303
1304 static struct pnp_driver cmos_pnp_driver = {
1305         .name           = (char *) driver_name,
1306         .id_table       = rtc_ids,
1307         .probe          = cmos_pnp_probe,
1308         .remove         = cmos_pnp_remove,
1309         .shutdown       = cmos_pnp_shutdown,
1310
1311         /* flag ensures resume() gets called, and stops syslog spam */
1312         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1313         .driver         = {
1314                         .pm = &cmos_pm_ops,
1315         },
1316 };
1317
1318 #endif  /* CONFIG_PNP */
1319
1320 #ifdef CONFIG_OF
1321 static const struct of_device_id of_cmos_match[] = {
1322         {
1323                 .compatible = "motorola,mc146818",
1324         },
1325         { },
1326 };
1327 MODULE_DEVICE_TABLE(of, of_cmos_match);
1328
1329 static __init void cmos_of_init(struct platform_device *pdev)
1330 {
1331         struct device_node *node = pdev->dev.of_node;
1332         const __be32 *val;
1333
1334         if (!node)
1335                 return;
1336
1337         val = of_get_property(node, "ctrl-reg", NULL);
1338         if (val)
1339                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1340
1341         val = of_get_property(node, "freq-reg", NULL);
1342         if (val)
1343                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1344 }
1345 #else
1346 static inline void cmos_of_init(struct platform_device *pdev) {}
1347 #endif
1348 /*----------------------------------------------------------------*/
1349
1350 /* Platform setup should have set up an RTC device, when PNP is
1351  * unavailable ... this could happen even on (older) PCs.
1352  */
1353
1354 static int __init cmos_platform_probe(struct platform_device *pdev)
1355 {
1356         struct resource *resource;
1357         int irq;
1358
1359         cmos_of_init(pdev);
1360         cmos_wake_setup(&pdev->dev);
1361
1362         if (RTC_IOMAPPED)
1363                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1364         else
1365                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1366         irq = platform_get_irq(pdev, 0);
1367         if (irq < 0)
1368                 irq = -1;
1369
1370         return cmos_do_probe(&pdev->dev, resource, irq);
1371 }
1372
1373 static int cmos_platform_remove(struct platform_device *pdev)
1374 {
1375         cmos_do_remove(&pdev->dev);
1376         return 0;
1377 }
1378
1379 static void cmos_platform_shutdown(struct platform_device *pdev)
1380 {
1381         struct device *dev = &pdev->dev;
1382         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1383
1384         if (system_state == SYSTEM_POWER_OFF) {
1385                 int retval = cmos_poweroff(dev);
1386
1387                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1388                         return;
1389         }
1390
1391         cmos_do_shutdown(cmos->irq);
1392 }
1393
1394 /* work with hotplug and coldplug */
1395 MODULE_ALIAS("platform:rtc_cmos");
1396
1397 static struct platform_driver cmos_platform_driver = {
1398         .remove         = cmos_platform_remove,
1399         .shutdown       = cmos_platform_shutdown,
1400         .driver = {
1401                 .name           = driver_name,
1402                 .pm             = &cmos_pm_ops,
1403                 .of_match_table = of_match_ptr(of_cmos_match),
1404         }
1405 };
1406
1407 #ifdef CONFIG_PNP
1408 static bool pnp_driver_registered;
1409 #endif
1410 static bool platform_driver_registered;
1411
1412 static int __init cmos_init(void)
1413 {
1414         int retval = 0;
1415
1416 #ifdef  CONFIG_PNP
1417         retval = pnp_register_driver(&cmos_pnp_driver);
1418         if (retval == 0)
1419                 pnp_driver_registered = true;
1420 #endif
1421
1422         if (!cmos_rtc.dev) {
1423                 retval = platform_driver_probe(&cmos_platform_driver,
1424                                                cmos_platform_probe);
1425                 if (retval == 0)
1426                         platform_driver_registered = true;
1427         }
1428
1429         if (retval == 0)
1430                 return 0;
1431
1432 #ifdef  CONFIG_PNP
1433         if (pnp_driver_registered)
1434                 pnp_unregister_driver(&cmos_pnp_driver);
1435 #endif
1436         return retval;
1437 }
1438 module_init(cmos_init);
1439
1440 static void __exit cmos_exit(void)
1441 {
1442 #ifdef  CONFIG_PNP
1443         if (pnp_driver_registered)
1444                 pnp_unregister_driver(&cmos_pnp_driver);
1445 #endif
1446         if (platform_driver_registered)
1447                 platform_driver_unregister(&cmos_platform_driver);
1448 }
1449 module_exit(cmos_exit);
1450
1451
1452 MODULE_AUTHOR("David Brownell");
1453 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1454 MODULE_LICENSE("GPL");